Based on our market monitoring, more than 60 active developers are currently offering residential property to foreign buyers on Koh Samui as of 2026. Some carry a multi-project track record in established areas such as Bophut, Maenam, and Lamai. Others are entities with no delivery history, registered only months before launching sales. The central question for any serious buyer is straightforward: to whom is it reasonable to commit staged payments during construction, given that Thailand does not operate buyer-protection payment structures equivalent to European standards?
Our analysts have been verifying developers on Koh Samui and Phuket for over eight years. The methodology below is what we apply in practice - step by step, with measurable warning thresholds.
Quick answer
- Based on our estimates, more than 30% of villa projects on Koh Samui experienced delays exceeding six months during 2022-2025
- Developers financing construction entirely from buyer deposits (no bank credit) represent elevated risk - in our data sets, such projects recorded delays two to three times more frequently than bank-backed ones
- Minimum required documentation: Construction Permit, EIA report (where applicable), Chanote title deed, and DBD company registration
- Payment schedules should be tied to verified construction milestones - a warning threshold is any demand for more than 40% of the purchase price before foundations are poured
- In Bophut and Maenam, our analysts identify eight to twelve developers with at least three completed and handed-over projects - that is our minimum qualification threshold
- Contractual delay penalties in standard Thai contracts typically run at 0.01-0.1% per day of the paid amount; we verify whether this clause is present and enforceable
Options and scenarios
Step 1 - Verifying the developer's track record
We verify on the ground how many projects a developer has actually completed and handed over. We cross-check company financials via the DBD (Department of Business Development) registry at datawarehouse.dbd.go.th, review the history of management changes, and map corporate ownership links. Our minimum threshold: three completed projects within the past seven years. A developer with a single delivery on record is categorised as elevated risk in our framework.
We also track historical time overruns. If prior projects were delivered more than six months late, we register that as a warning signal. A delay exceeding twelve months on more than one project is, in our assessment, grounds to withhold a recommendation entirely.
Step 2 - Construction financing structure
This is one of the most consequential elements of our analysis. A developer on Koh Samui can finance construction through three channels: a bank loan, equity capital, or buyer deposits. In practice, most smaller developers operating in Lamai and Chaweng use a mixed model - partial own funds combined with staged buyer payments.
We ask directly about the financing structure and request supporting documentation. A developer with an approved bank loan (for example from Bangkok Bank or Kasikornbank) has already passed a financial institution's own credit review - that represents an additional verification layer. Based on our estimates, only 25-30% of villa projects on Koh Samui in 2026 carry a confirmed construction bank loan.
Step 3 - Payment schedule versus construction progress
Thailand has no statutory requirement for developers to hold foreign buyer payments in any form of protected account. Payments transfer directly to the developer. As a result, we treat the payment schedule itself as the primary buyer-protection mechanism. A schedule we consider structurally sound looks like this:
- Reservation and contract: 5-10%
- Foundations completed: 15-20%
- Shell structure completed: 20-25%
- Interior fit-out: 20-25%
- Key handover: 20-30%
Our warning threshold: if a developer demands more than 50% of the price before the shell structure is complete, we rate that risk as unacceptable.
Step 4 - Quality inspection of prior projects
Our analysts visit previously completed developments in person. We assess technical condition after two to five years of occupation: quality of waterproofing membranes (particularly critical in Koh Samui's tropical climate), electrical installation standards, drainage system performance, pool construction, and condition of communal areas. We speak directly with owners and property managers in Bophut, Maenam, and Lamai.
Step 5 - Completeness of permits and land documentation
We verify five documents as a baseline:
- Chanote (Nor Sor 4 Jor) - the highest-grade land title in Thailand
- Construction Permit - issued by the relevant local authority (Tessaban or OrBorTor)
- EIA (Environmental Impact Assessment) - required for projects exceeding 80 units or located on environmentally sensitive land
- DBD company registration - with full financial history
- Land Subdivision Permit - required where a project involves more than nine plots
In our practice, the absence of any document that is legally required constitutes an unconditional basis to withhold a recommendation.
Step 6 - Sales contract analysis
We review contracts for several critical clauses: delay penalties (we look for a minimum of 0.05% per day), termination conditions, precise material and finish specifications, a handover deadline with a tolerance of no more than 90 days, and a dispute resolution mechanism (we prefer THAC arbitration in Bangkok over general court proceedings).
Step 7 - Local market reputation check
We monitor local property owner communities on Koh Samui, expat group forums, and Thai court records for litigation history. This step cannot be conducted remotely - it requires physical presence on the island.
Comparison table
| Parameter | Class A Developer | Class B Developer | Class C Developer (higher risk) |
|---|---|---|---|
| Completed projects | 5 or more | 3 to 4 | 0 to 2 |
| Average delay | Up to 3 months | 3 to 6 months | Over 6 months |
| Financing structure | Bank loan plus own equity | Own equity plus buyer deposits | Buyer deposits only |
| Payment before foundations | Up to 25% of price | 25 to 40% of price | Over 40% of price |
| Delay penalty clause | 0.05 to 0.1% per day | 0.01 to 0.05% per day | Absent or nominal |
| Documentation | Complete, provided proactively | Complete on request | Incomplete or withheld |
| Prior project condition | Good condition after 3-5 years | Minor defects visible | Structural defects present |
| DBD balance sheet | Positive equity | Low but positive equity | Negative equity or no data |
In our 2026 dataset for Koh Samui, we identify 8 to 10 Class A developers, concentrated mainly in Bophut and Maenam, and 12 to 15 Class B developers. The remainder qualify as Class C under our framework.
Risks and mistakes
Risk 1: No independent on-the-ground verification. Buyers who purchase remotely, relying solely on marketing materials and CGI renders, skip physical inspection. In our practice, at least 20% of Koh Samui projects present significantly better in renders than in reality.
Risk 2: Assuming buyer payments are held in a protected account. Thailand does not operate a European-style buyer payment protection system for foreign real estate purchasers. Payments go directly to the developer's account. The only substantive protections are a milestone-linked payment schedule and the developer's own financial strength.
Risk 3: Purchasing through an agent without verifying their authorization. Many agents on Koh Samui market projects without a formal agreement with the developer. We verify whether any agent involved holds official developer authorization.
Risk 4: Ignoring the company balance sheet. Thai company financials are publicly accessible via the DBD registry. A developer showing negative equity or three consecutive years of losses is, in our assessment, a signal that project completion may be at risk.
Risk 5: Currency exposure. Buyers paying in Thai Baht (THB) face exchange rate movement across a construction period. With THB exchange rates fluctuating in 2026, a payment schedule spread over 18 months can generate currency exposure of roughly 5-10% of the investment value, depending on the buyer's home currency.
FAQ
How do we verify a developer on Koh Samui before purchase?
The first step is checking the company record in the DBD registry (datawarehouse.dbd.go.th) - registration date, registered capital, board composition, and financial results. We then visit the developer's prior projects on the island, review the sales contract, and verify the completeness of all required construction permits.
Are there protected buyer payment accounts in Thailand?
No. Thailand does not operate a buyer payment protection mechanism for foreign real estate purchasers equivalent to European standards. Payments transfer directly to the developer. The practical protections are a milestone-tied payment schedule, contractual delay penalties, and the developer's verified financial stability.
How many completed projects should a developer have?
Our minimum threshold is three completed and handed-over projects within the past seven years. Developers with five or more completed projects on Koh Samui qualify for our highest trust category.
What payment schedule is considered safe for a Koh Samui villa purchase?
A structurally sound schedule caps payments at 25-30% before foundations are complete, with 20-30% retained until key handover. Any demand for more than 50% of the price before the shell structure is finished is, in our assessment, an unacceptable risk level.
How do we check construction permits in Thailand?
The Construction Permit is issued by the local authority - Tessaban or OrBorTor. We request a copy from the developer and cross-check the permit number directly with the issuing office. We also confirm that the permit scope covers the actual planned build.
How long does a full developer due diligence process take?
Our complete due diligence process runs 5 to 10 working days, covering documentation review, on-site inspection, registry verification, and contract analysis.
Can a buyer conduct due diligence remotely?
Part of the process can be done remotely - DBD registry checks, contract review, and permit number verification. However, physical inspection of prior project quality, conversations with existing owners, and live construction site assessment require presence on Koh Samui or Phuket.
What are typical construction delays for villas on Koh Samui?
Based on our market monitoring data from 2022-2025, the median delay for villa projects on Koh Samui is 3 to 4 months. Class A developers typically stay within a three-month overrun, while developers without a delivery history frequently exceed deadlines by six to eighteen months.
Does the due diligence methodology differ between Phuket and Koh Samui?
The analytical structure is identical. The practical difference is market scale - in Phuket (particularly in Bang Tao, Layan, Kamala, and Surin) a larger proportion of developers carry confirmed bank financing. On Koh Samui, Class B developers are more dominant, making financial verification correspondingly more important.
What does professional developer due diligence cost in Thailand?
Independent legal review of a sales contract typically runs 15,000 to 30,000 THB. A full due diligence package covering technical inspection and land title verification ranges from 30,000 to 60,000 THB, based on our estimates for 2026 market rates.
We apply this methodology consistently to every developer we assess on Koh Samui and Phuket, regardless of project scale. In our practice, rigorous pre-commitment screening eliminates approximately 40% of projects under consideration at the documentation review stage alone. That filter is more effective at protecting buyer capital than any developer's marketing materials.
Researching property in Phuket or Koh Samui? Get in touch - our analysts will prepare a data brief for your shortlisted location.